It started out as a modest desire to run the 700W microwave (that actually pulls about 1200 watts) without being plugged in or starting the generator. I also wanted to get rid of 150 year old lead-acid technology and double my usable amp hours so we could boondock more than one night. Modest goals I thought.
All parts of my project are Renogy (except for Victron 75/15 Bluetooth solar controller replaced last year). Mainly because the Renogy's were the only batteries that fit (and their prices are right). I guess I was feeling flush with cash when Renogy put their 100Ah lithium batteries on sale for $719 (no tax, no shipping) back in August, I took the plunge and ordered two. After initially ordering a 2000W inverter without charger, I realized it would be easier to install a combined inverter/charger. Sent it back and reordered. The first combined inverter/charger had a recall the day after I received it, so had to wait for a replacement. This accounts for considerable delay in completing my project.
To bring you up to date:
Inverter/charger - Replaced the old 750 Tripplite with the Renogy 3000W Pure Sine Wave Lithium Compatible R-INVT-PCL1-30111S-BC. Currently on sale for $719 (free shipping
https://www.renogy.com/3000w-12v-pur...w-lcd-display/). It happened to just fit the long and fairly skinny space I had available. Overkill for now, but I wanted the 3000W in case of future upgrades.
Truly an easy plug & play replacement for the Tripplite. It is easily programmed from it's top LCD screen. Charger rates can be set in 5A increments up to 65A. I set the charge rate for 45 amps which is the same as the old Tripplite on high charge. A comparable Victron will run you about $1300. A respected product, but at nearly twice the cost.
2 x 100Ah Lithium Batteries - Besides being on sale for $719 at the time I purchased, Renogy had the only true Group 27 sized batteries I found (actually slightly smaller). Battleborns, besides being more expensive, simply wouldn't fit externally or internally in my application. I ended up installing the Renogy's inside, next to the inverter, by re-purposing a small storage compartment. Makes for short cable runs of 24" for everything but the Inverter positive, which is still only 36". I just purchased all new cables except for the 2ga parallel cables from the old batteries.
DC-DC Charger - At the time, Renogy offered 20A ($129) and 40A ($179) models. I chose the 40A since I figured the 20 wasn't enough and the 40 would still not over-tax my engine alternator (just my guess). I effectively isolates the lithiums from the lead-acid engine battery bypassing the old Isolator to which the Ignition switch was wired. This required I move the Ignition wire that turns on the DC-DC charger on to new charger and running a new ground.
State of Charge Monitor/Shunt - To track the lithium charge levels, I purchased the Renogy 500A Monitor for $99. Comes with it's own shunt which is wired to the negative cables. It handles 500 amps and can be programmed for up to 9999 amp hours of battery, so again, I won't have to replace it if I add future battery capacity.
Unexpected Discoveries during install:
While the install when pretty much as expected and there was no smoke or fires (thanks uncle bob)
, moving the batteries inside and disconnecting from the chassis battery resulted in the following unwanted, but necessary changes.
1) The chassis battery no longer charges when plugged in.
I also no longer have the battery boost feature that allows a weak engine battery to be started from coach batteries.
Guess I'll have to buy and carry a $200 battery booster now.
2) The old battery cables to the outside are no longer used, and so, no longer power the main 12 DC bus. So I had to add a cable from the relocated batteries to the positive DC bus to power the coach's 12 DC panel. Also had to relocate the Tank Monitor power from the old Isolator location where they were no longer getting power. Both were minor, just unexpected.
3) One of the major reasons for the upgrade was to run the microwave from the inverter. But I soon realized the plug behind the microwave is
not on the inverter curcuit. Oops.
We are leaving on a trip in a week so I temporarily ran an extension cord behind the cabinets to the a wall outlet connected to the inverter. A permanent fix will have to wait.
4) Love how fast the batteries charge with the new system. However, the inverter fan (which only runs intermittently under load) is noticeably noisier than the old Tripplite.
Still, we don't plan to run the inverter except to use power-hungry appliances like the Microwave or a hair dryer and they will drown out any additional noise from the inverter.
Thoughts and future plans:
I just hate the old technology of lead-acid batteries and am glad to have them gone. So far I'm in for about $2700 and that is "doing it on the cheap". I am wondering if the upgrade is worth it for the incremental benefit. Rationally no, but if there were truly a plug & play lithium battery option that worked with existing components, then for sure I'd say yes.
In my wildest dreams, there may someday be a 15,360wh beast lurking inside the old Avenue. Something that crushes the new "National Parks Edition" Travato and Boldt since I have room under the rear lounge to add up to 10 more 100ah lithiums (total of 12 x 1280wh) and still only take up a little more than half the available area.
Of course, it's just a little matter of $8000, an Easy-Start, and helalot of huge cables. Plus jettisoning the old Onan generator to keep weight to current levels.
Oh the dreams of youth (at age 65)!
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